I have flagged this answer as "not an answer" - the description of the flag is:
This was posted as an answer, but it does not answer the question. It should possibly be an edit, a comment, another question, or deleted altogether.
This was declined as:
flags should not be used to indicate technical inaccuracies, or an altogether wrong answer
In this specific case, the answer given does not answer the question. It is on a tangent that is entirely unrelated to the question and the issue the OP is having.
How should I have handled/flagged this?
How should one flag "answers" that have nothing to do with the question - not answers that are wrong, but simply completely unrelated?
I find the description of the "not an answer" flag misleading in view of the decline reason.
I had originally commented on this answer, asking the poster what relationship it has to the question (or words to that effect) - the comment was removed, probably by the same moderator.